Information

21.3.7 Clear Enable Request Register (DMA_CERQ)
The CERQ provides a simple memory-mapped mechanism to clear a given bit in the
ERQ to disable the DMA request for a given channel. The data value on a register write
causes the corresponding bit in the ERQ to be cleared. Setting the CAER bit provides a
global clear function, forcing the entire contents of the ERQ to be cleared, disabling all
DMA request inputs. If NOP is set, the command is ignored. This allows you to write
multiple-byte registers as a 32-bit word. Reads of this register return all zeroes.
Address: DMA_CERQ is 4000_8000h base + 1Ah offset = 4000_801Ah
Bit 7 6 5 4 3 2 1 0
Read 0 0 0
Write NOP CAER 0 CERQ
Reset
0 0 0 0 0 0 0 0
DMA_CERQ field descriptions
Field Description
7
NOP
0 Normal operation
1 No operation, ignore the other bits in this register
6
CAER
Clear All Enable Requests
0 Clear only the ERQ bit specified in the CERQ field
1 Clear all bits in ERQ
5–2
Reserved
This field is reserved.
1–0
CERQ
Clear Enable Request
Clears the corresponding bit in ERQ
Memory map/register definition
K20 Sub-Family Reference Manual, Rev. 2, Feb 2012
350 Freescale Semiconductor, Inc.